Vacuum preforming of bamboo fiber mat into curved shapes and composite fabrication

This study aims to understand the vacuum preforming process of bamboo fiber mats and utilize the preforms to fabricate composites through vacuum-assisted resin transfer molding. Bamboo fibers were woven into a unidirectional mat with polyester threads and were then vacuum-formed to a curved shape with a constant curvature. For convex shapes, vacuum preforming can produce a preform with good dimensional accuracy. However, for concave shapes, the preform tends to have a significant corner radius deviation. Using a lead caul plate and aluminum rod in the preforming process has been shown to effectively reduce the corner radius deviation of the preform. Raising the temperature during preforming can reduce the corner radius deviation as well. Bamboo fiber mat with fibers oriented at 0° exhibits better conformity with the mold during preforming compared to 90°. After molding the composite using the bamboo fiber mat, a smaller difference in corner radius between the preforms and the mold shape can lead to lower thickness deviations in the composite’s corner region.